Intel spent most of its press conference yesterday talking about future products, but there was one announcement with a more immediate impact: new 7 watt Ivy Bridge processors are shipping to Intel's partners now for inclusion in products this spring and summer.

These new CPUs appear to represent quite a substantial power savings over the processors shipping in most Ultrabooks today, which have a 17 watt TDP, but Intel's marketing slides don't quite tell the whole story. We talked with Intel representatives, went hands-on with Lenovo's IdeaPad Yoga 11S, and did some sleuthing on Intel's CPU product pages to see what kind of power consumption and performance we can actually expect from these processors.

“Scenario Design Power”

The particular Ivy Bridge processor in the IdeaPad 11S we got our hands on was a Core-i5 3339Y, a 1.5GHz dual-core processor with Hyperthreading and Turbo Mode support up to 2.0GHz. There are both cheaper and more expensive CPUs in the lineup, but this one probably represents the best combination of features and price—we expect it will be one of the more popular selections for Ultrabooks and tablets based on these processors, much like the Core i5-3317U is now.

Detailed information on this processor is up on Intel's ARK site for anyone who bothers to look it up, and it immediately reveals a bit of fancy footwork on Intel's part: the actual thermal design power (TDP) of that processor is listed at 13 watts. The 7 watt number advertised during Intel's keynote yesterday is actually from a new metric, "scenario design power" (SDP), which purports to measure how much power the CPU is using during average use.

SDP is a new unit of measurement for Intel, and the company doesn't list an SDP number for its current 17 watt low-voltage processors. These new processors do save power compared to previous models, but in an apples-to-apples comparison it only ends up to be about 4 watts, not the 10 watt savings it appears to be in Intel's marketing slides.

Intel's "7 watt" Y-series CPUs

CPU

CPU Clock/Turbo speed

CPU cores/threads

GPU

GPU base/max speed

Max TDP

SDP

Pentium 2129Y

1.1GHz

2/2

Intel HD Graphics

350/850MHz

10W

7W

Core i3-3229Y

1.4GHz

2/4

Intel HD Graphics 4000

350/850MHz

13W

7W

Core i5-3339Y

1.5GHz/2GHz

2/4

Intel HD Graphics 4000

350/850MHz

13W

7W

Core i5-3439Y

1.5Ghz/2.3GHz

2/4

Intel HD Graphics 4000

350/850MHz

13W

7W

Core i7-3689Y

1.5GHz/2.6GHz

2/4

Intel HD Graphics 4000

350/850MHz

13W

7W

Note that there is one processor which manages a 10 watt TDP, the low-end Pentium 2129Y. That processor's lowly 1.1GHz clock speed, weaker GPU, and lack of features like Hyperthreading and Turbo Mode mean that it's probably destined mostly for budget systems, however.

Performance

Neither Intel nor Lenovo would let us run any of our benchmarks on their pre-release IdeaPad 11S units, but the ARK product pages tell us most of what we need to know about the processors' performance. Let's compare the i5-3339Y to the popular (and roughly analogous) 17 watt processor, the i5-3317U.

CPU face-off: 17 Watt vs. 13 Watt

CPU

CPU Clock/Turbo speed

CPU cores/threads

GPU

GPU base/max speed

Max TDP

SDP

Core i5-3339Y

1.5GHz/2GHz

2/4

Intel HD Graphics 4000

350/850MHz

13W

7W

Core i5-3317U

1.7GHz/2.6GHz

2/4

Intel HD Graphics 4000

350/1050MHz

17W

N/A

These CPUs feature the same basic features, graphics processors, and manufacturing processes, so if you're going to save power there's really only one thing to cut: clock speed. The Y-series processor only loses a little in base clock speed—1.5GHz compared to 1.7GHz—but you lose 600MHz in Turbo Boost speed, which could result in as much as a 23 percent reduction in single-threaded performance, assuming that performance scales linearly with clock speed.

These chips will still be plenty fast for the kinds of tasks that Ultrabooks based on U-series CPUs usually perform—word processing, Web browsing, and on-the-go photo and video processing. Whether you notice the speed hit in real-world usage will depend on the kinds of tasks you usually do.

You also lose some graphics speed, though thankfully you retain all of the core features of Intel's HD 4000-series GPU, including QuickSync, Wireless Display, and support for APIs like DirectX 11, OpenGL 4.0, and OpenCL 1.1. The base graphics frequency of 350MHz is the same, but the Y-series chip tops out at 850MHz, down from 1.05GHz in the U-series chip. Again assuming performance that scales fairly linearly with clock speed, you'll lose about 19 percent of your performance compared to the analogous U-series CPU (and slightly more in CPU-bound games that are also adversely affected by the drop in CPU clock speed).

We'll continue trying to get our hands on a system for some actual benchmarking, and we'll update this article if we're granted access to one of the pre-production systems.

Conclusions

In the end, Intel has saved power in its new Y-series CPUs in the least surprising way possible—not through improvements to the 22nm manufacturing process or aggressive processor binning, but through clock speed reductions and some fancy marketing footwork.

The new CPUs are more power efficient, but not massively so. It's also worth noting that the CPU is but one piece of the puzzle in your PC—the RAM, disk, monitor, and other components also need to be accounted for—this, plus the actual 13 watt TDP of these new Ivy Bridge processors, helps to explain why PCs like Microsoft's Surface Pro (which is rumored to be using these newer Y-series CPUs) still have mediocre battery life.

What this all means is that, though these Y-series CPUs will enable slightly thinner and more power efficient designs in the short term, we're still going to be waiting for Haswell to see big reductions in power usage. Though our Intel rep told us that the TDP and SDP numbers for low-voltage Haswell processors are expected to be about the same as these Ivy Bridge models (unsurprising, given that they're both produced on the same 22nm manufacturing process), remember that Haswell is also bringing a few more power-saving technologies to bear. The most notable of these are the new "active idle" power states that allow systems to go to sleep more quickly, more often, and more transparently than today's PCs.

Update: In an earlier version of this article, we gave an Intel's representative's estimate of an SDP number for the U-series Ivy Bridge processors. We have been told that that number is not accurate, and that Intel doesn't have SDP figures for these processors.

Promoted Comments

Seems like this would have been more exciting had Intel not played up the 7W claim, only to find that it requires a new asterisk. I think it does say something about how good Ivy Bridge can be, but I walk away with the thought that Intel basically stole their own thunder.

The ad needs to be "Check out Intel's new lower speed chips! They use proportionately less power!"

Another option is to run the chip at 0 GHz and use 0 Watts. Now that's efficient!

1847 posts | registered Oct 4, 2005

Andrew Cunningham
Andrew has a B.A. in Classics from Kenyon College and has over five years of experience in IT. His work has appeared on Charge Shot!!! and AnandTech, and he records a weekly book podcast called Overdue. Twitter@AndrewWrites

26 Reader Comments

These CPUs feature the same basic features, graphics processors, and manufacturing processors, so if you're going to save power there's really only one thing to cut: clock speed.

There's also better binning and yield improvements, meaning that the cpu could run at a lower voltage. It could be that the new chips can't hit the same turbo speeds, but are very happy running at lower voltage.

Seems like this would have been more exciting had Intel not played up the 7W claim, only to find that it requires a new asterisk. I think it does say something about how good Ivy Bridge can be, but I walk away with the thought that Intel basically stole their own thunder.

SDP seems like the more meaningful metric, considering you aren't likely to be at peak usage for long periods of time. So according to the SDP, it's almost a 50% reduction. Even still, going from 17W TDP to 13W TDP is almost a 25% reduction. Another question I would have is what is idle like? If they both draw 1W at idle, where these computers are going to spend most of their time anyway, then there is little actual benefit. And on top of that, you're still going to have to combine these reductions with other components that are also more efficient to see any real difference.

Why do writers assume that low-powered computers are good enough for Web browsing? Web browsing encompasses lots of different applications. Even normal web pages these days require a fair amount of CPU to render and memory to hold. And interactive web pages can challenge even desktops' performance.

I wouldn't want to do my daily work, which largely consists of word processing, spreadsheets, and web browsing, using a CPU with these specs. I'd deal with the slightly shorter battery life of a more capable ultrabook.

Why do writers assume that low-powered computers are good enough for Web browsing? Web browsing encompasses lots of different applications. Even normal web pages these days require a fair amount of CPU to render and memory to hold. And interactive web pages can challenge even desktops' performance.

I wouldn't want to do my daily work, which largely consists of word processing, spreadsheets, and web browsing, using a CPU with these specs. I'd deal with the slightly shorter battery life of a more capable ultrabook.

"General use" is hard to define, but I don't think it's unreasonable to say that a dual-core Ivy Bridge processor in any form will be quick enough for most people. I know you guys aren't "most people," but still... :-)

"Note that there is one processor which manages a 10 watt TDP, the low-end Pentium 2129Y. That processor's lowly 1.1GHz clock speed, weaker GPU, and lack of features like Hyperthreading and Turbo Mode mean that it's probably destined mostly for budget systems, however."

This is probably in the same total platform power as the first generation netbooks (11.8W CPU + NB + SB); while providing much higher performance than any atom based solution; combined with larger ultrabook size batteries the 10hrs of runtime we saw with some of the most efficient netbooks might become available again.

Why do writers assume that low-powered computers are good enough for Web browsing? Web browsing encompasses lots of different applications. Even normal web pages these days require a fair amount of CPU to render and memory to hold. And interactive web pages can challenge even desktops' performance.

I wouldn't want to do my daily work, which largely consists of word processing, spreadsheets, and web browsing, using a CPU with these specs. I'd deal with the slightly shorter battery life of a more capable ultrabook.

All power savings features make for a poor user experience, nut it is better than being dead in the water (no power). The constant turning off the backlight to save power is most annoying. If given a choice, I use a desktop computer with a big ass monitor and real keyboard.

The vast majority of notebook users are not far away from a power source. Look at the coffee shop crowd. Peets is putting in tables and power outlets. For office workers, the bring the notebook to the conference room. Again, they could have power if the table was wired. Few users are actually in the field (no nearby power.)

I don't know about the current generation ultrabooks, but if you can't slap in a spare battery, it is not a truly mobile device. The same goes for smartphones. Yeah fanbois, vote me down, but that is reality.

SDP seems like the more meaningful metric, considering you aren't likely to be at peak usage for long periods of time.

I'm not sure I disagree, but I don't entirely agree. On the one hand it is true that TDP can be misleading in this age of turbo boost and power gating, given that TDP represents the worst-case scenario. On the other, SDP seems like a very subjective measure. What is the scenario Intel envisions, and is that the same for all of their chips? What if Haswell misses its power consumption targets, can Intel modify its metric again to get the "savings" it needs on paper?

TDP is nice and concrete, as a physical specification with physical implications. TDP defines your cooling requirements. Show me a lower TDP and I'll show you a thinner heatsink and where to fit a thicker battery.

This sounds like it's Intel's version of Apple's performance-per-watt metric that they touted as the reason to switch to Intel in the first place. Yes it's a good metric, and yes it's a useful metric, but no it's not the same metric, and no it doesn't tell the whole story.

And like we saw if we read between the lines, all it means is that if you underclock a CPU, it uses less power. Shocking.

Thank you for reporting this. I was having a hard time figuring out how they were getting 7W parts just from a process shrink.

Are we getting to the point where power savings on the CPU are being overly focused on at the detriment of power reduction of other components? Specifically the power usage of a LCD display in the ultra book class notebooks.

These CPUs feature the same basic features, graphics processors, and manufacturing processes, so if you're going to save power there's really only one thing to cut: clock speed.

Or, like BigLan noted, through reduced core voltage - something that does get easier to pull off when you reduce the clockspeed, but binning can also help there.

Quote:

In the end, Intel has saved power in its new Y-series CPUs in the least surprising way possible—not through improvements to the 22nm manufacturing process or aggressive processor binning, but through clock speed reductions and some fancy marketing footwork.

Are you sure about this?I don't see core voltage numbers on the ARK pages. Do you have any other sources that claim that the core voltage is the same for both processors, or are you speculating?

With the way Intel has been firing on all cylinders lately, I thought they were pulling out something nearly-miraculous when they started talking about 10W IB processors.

This, though, isn't it. This is some bullshit marketing. I could talk about how efficient my Phenom II is since it doesn't spend most of its life under heavy load. Instead, I know that it's an 80W processor at stock. To talk as if its anything else would be a lie. I could clock it way down and undervolt it, but that doesn't fundamentally change what it is.

What Intel has done is not technically lie (they do have the one, even though it won't be good for much), but this is a little sleazy.

Is there any real wonder about the ARM lock down for Windows 8 devices?

Many have cited that performance issues warrant not running rebuilt desktop apps on these machines. IMHO, that's fair, but nobody is talking about the idea that many things could be rebuilt to operate in a more lean way, nor how users may well make trade-offs not very well aligned with the best interests of both manufacturers.

Intel has done a lot of engineering along a specific path and the market dynamics have changed a little, favoring ARM, who engineered a different way.

Normally, this kind of thing would be good for users over the long haul, but there are clear moves here to keep things highly differentiated through code, not any kind of market selection.

The ad needs to be "Check out Intel's new lower speed chips! They use proportionately less power!"

Another option is to run the chip at 0 GHz and use 0 Watts. Now that's efficient!

I do wish my i5 laptop had more lower speed steps. It can only go as low as 1.2ghz. If I limit the CPU to 1.2ghz, I can disconnect the CPU fan but I have to keep the bottom off for more airflow. If there was an option for 600mhz operation, I bet I could put the bottom lid back on.

It's nice they're now offering more low speed options ... but it just reinforces how Intel artificially removes features from CPUs to segment their market. Just like how they decide X chips don't get 64-bit (in the past), Y chips don't get hardware virtualization, Z chips don't get power saving (in the past), etc. Want a low power version running at half the mhz? Why that'll be double the price!

SDP seems like the more meaningful metric, considering you aren't likely to be at peak usage for long periods of time. So according to the SDP, it's almost a 50% reduction. Even still, going from 17W TDP to 13W TDP is almost a 25% reduction. Another question I would have is what is idle like? If they both draw 1W at idle, where these computers are going to spend most of their time anyway, then there is little actual benefit.

Well in day to day use, yes maybe. But the point here is that during design, we don't look at average usage (in this context SDP) but worst case senario (ie TDP). This design consist of various things like thermal management, air flow, GPU output, battery life etc. Also realize that battery technology is not linear, their are internal resistence which account for more than what you can get from a linear coverage. As an example, if i drop 1 watt in TDP, i get 15 minutes more battery life (just a example) then dropping 2 watts usually lands up with >30 minutes (around 38-40 minutes, <- guess work here). On the flip side, even if i hold SDP at a point and increase TDP, we usually land up with way worser numbers for physical reasons like non linear battery charactersitics and bigger active heat sinks (basically more power to run larger fans).

Why do writers assume that low-powered computers are good enough for Web browsing? Web browsing encompasses lots of different applications. Even normal web pages these days require a fair amount of CPU to render and memory to hold. And interactive web pages can challenge even desktops' performance.

I wouldn't want to do my daily work, which largely consists of word processing, spreadsheets, and web browsing, using a CPU with these specs. I'd deal with the slightly shorter battery life of a more capable ultrabook.

The manufacturers could also give up the stupid thinner is better extremism and just put in a decent battery in the laptops. Who gives a rats ass about 1-2 mm. If you don't have to carry around the charger it's already much better option.

SDP seems like the more meaningful metric, considering you aren't likely to be at peak usage for long periods of time.

I'm not sure I disagree, but I don't entirely agree. On the one hand it is true that TDP can be misleading in this age of turbo boost and power gating, given that TDP represents the worst-case scenario. On the other, SDP seems like a very subjective measure. What is the scenario Intel envisions, and is that the same for all of their chips? What if Haswell misses its power consumption targets, can Intel modify its metric again to get the "savings" it needs on paper?

TDP is nice and concrete, as a physical specification with physical implications. TDP defines your cooling requirements. Show me a lower TDP and I'll show you a thinner heatsink and where to fit a thicker battery.

IIRC even TDP is not really well defined. Isn't it that AMD used to provide absolute worst case scenario while Intel did some kind of normally it should stay under this number kind of thing?

Why do writers assume that low-powered computers are good enough for Web browsing? Web browsing encompasses lots of different applications. Even normal web pages these days require a fair amount of CPU to render and memory to hold. And interactive web pages can challenge even desktops' performance.

I wouldn't want to do my daily work, which largely consists of word processing, spreadsheets, and web browsing, using a CPU with these specs. I'd deal with the slightly shorter battery life of a more capable ultrabook.

"General use" is hard to define, but I don't think it's unreasonable to say that a dual-core Ivy Bridge processor in any form will be quick enough for most people. I know you guys aren't "most people," but still... :-)

It's stunning to see those clock speeds and realize they're basically the same as for phones. Yes, the Intel ultrabook chips are noticeably better, but it's close now.

Yes, these are ultrabook chips meant for ultra-portability, but see how the chip speed race is over. Intel has been working on efficiency for years, and now their mainstream new chips are actually getting slower.

Thank you for reporting this. I was having a hard time figuring out how they were getting 7W parts just from a process shrink.

Are we getting to the point where power savings on the CPU are being overly focused on at the detriment of power reduction of other components? Specifically the power usage of a LCD display in the ultra book class notebooks.

For Haswell Intel is recommending a full set of components/firmware versions to minimize off CPU power consumption.

SDP seems like the more meaningful metric, considering you aren't likely to be at peak usage for long periods of time. So according to the SDP, it's almost a 50% reduction. Even still, going from 17W TDP to 13W TDP is almost a 25% reduction. Another question I would have is what is idle like? If they both draw 1W at idle, where these computers are going to spend most of their time anyway, then there is little actual benefit.

Well in day to day use, yes maybe. But the point here is that during design, we don't look at average usage (in this context SDP) but worst case senario (ie TDP). This design consist of various things like thermal management, air flow, GPU output, battery life etc. Also realize that battery technology is not linear, their are internal resistence which account for more than what you can get from a linear coverage. As an example, if i drop 1 watt in TDP, i get 15 minutes more battery life (just a example) then dropping 2 watts usually lands up with >30 minutes (around 38-40 minutes, <- guess work here). On the flip side, even if i hold SDP at a point and increase TDP, we usually land up with way worser numbers for physical reasons like non linear battery charactersitics and bigger active heat sinks (basically more power to run larger fans).

You size the battery for a worst-case use scenario? Doesn't that have to be a miss-statement?

I find it hard to believe that any laptop manufacturer bases battery size on the analysis "Intel says TDP is __ Watts, and we want __ hours of life, the other components draw __ Watts, so the battery needs to be ____ Wh."

I understand thermal design needs to account for the worst-case usage. If someone has a laptop plugged in and is running something very processor and GPU intensive, you've got to be able to move all that heat. But it seems like battery life specs tend to be targeted to some kind of "real world" usage: __ hours of surfing over wifi and __ hours of watching video, for example.

I envision the following conversation has happened at basically every laptop manufacturer:

Engineer: We're hitting the battery life metrics for general use and watching video that we targeted. However, Intel's new CPU can draw so much power in heavy-use tasks that we take a real hit on battery life if the user is doing anything with heavy draw.

Manager: There's always going to be a scenario that blows through the battery. That's what the power cord is for. Let's just focus on the metrics we already decided on.

Bummer. Now I feel like a fool for believing their 7 watt claim; I've been quoting that as TDP, only to find that, as usual, Intelspeak can't be taken at face value. Thanks Intel! Now I'll have to go back and publicly repudiate that number. How's that PR coup working out for you, Intel?

Intel needs the equivalent of "22nm process" values for their marketing, since their gains are coming from marketing "improvements" now.

I remember when they were all about MHz, until they hit a wall and started talking about per-cycle efficiency. Now that their wattage reductions are minimal, they reduce clockspeed and use a new measurement without telling anyone. Genius! /s